When liquid substances and particularly liquid chemicals are poured or dispensed from a conventional barrel or drum it does not become completely empty. Some of the liquid remains in the drum regardless of whether its contents are poured out through the bunghole or removed by a pump or siphon dip tube. The contents remaining in the drum create disposal and environmental problems and are an economic waste of the remaining liquid chemicals. The remaining liquid chemicals must be removed from the drum and disposed of in an environmentally safe manner and the drum cleaned before it can be reused or disposed of. Therefore there are substantial economic costs associated with the failure of a drum to become completely empty or drained out in the ordinary course of dispensing its contents.